Organometallic compound, organic light-emitting device including the organometallic compound, and diagnostic composition including the organometallic compound

ABSTRACT

An organometallic compound represented by Formula 1:M(L1)n1(L2)n2  Formula 1wherein M, L1, L2, n1, and n2 are the same as described in the specification.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation application of U.S. application Ser. No. 15/933,763, filed on Mar. 23, 2018, which claims priority to Korean Patent Application No. 10-2017-0036916, filed on Mar. 23, 2017, in the Korean Intellectual Property Office, and all the benefits accruing therefrom under 35 U.S.C. § 119, the contents of which are incorporated herein in their entirety by reference.

BACKGROUND 1. Field

One or more embodiments relate to an organometallic compound, an organic light-emitting device including the organometallic compound, and a diagnostic composition including the organometallic compound.

2. Description of the Related Art

Organic light-emitting devices (OLEDs) are self-emission devices, which have superior characteristics in terms of a viewing angle, a response time, a brightness, a driving voltage, and a response speed, and produce full-color images.

A typical organic light-emitting device includes an anode, a cathode, and an organic layer disposed between the anode and the cathode, wherein the organic layer includes an emission layer. A hole transport region may be disposed between the anode and the emission layer, and an electron transport region may be disposed between the emission layer and the cathode. Holes provided from the anode may move toward the emission layer through the hole transport region, and electrons provided from the cathode may move toward the emission layer through the electron transport region. The holes and the electrons recombine in the emission layer to produce excitons. These excitons transit from an excited state to a ground state, thereby generating light.

Meanwhile, luminescent compounds may be used to monitor, sense, or detect a variety of biological materials including cells and proteins. An example of the luminescent compounds includes a phosphorescent luminescent compound.

Various types of organic light emitting devices are known. However, there still remains a need in OLEDs having low driving voltage, high efficiency, high brightness, and long lifespan.

SUMMARY

One or more embodiments include a novel organometallic compound, an organic light-emitting device including the organometallic compound, and a diagnostic composition including the organometallic compound.

Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.

According to one or more embodiments, an organometallic compound is represented by Formula 1: M(L₁)_(n1)(L₂)_(n2)  Formula 1

M in Formula 1 may be selected from iridium (Ir), platinum (Pt), osmium (Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), thulium (Tm), rhodium (Rh), ruthenium (Ru), and rhenium (Re),

-   -   in Formula 1, L₁ may be a ligand represented by Formula 2, and         n1 may be 1, 2, or 3, wherein, when n1 is two or more, two or         more groups L₁ may be identical to or different from each other,     -   in Formula 1, L₂ may be selected from a monovalent organic         ligand, a divalent organic ligand, a trivalent organic ligand,         and a tetravalent organic ligand, and n2 may be 0, 1, 2, 3, or         4, wherein, when n2 is two or more, two or more groups L₂ may be         identical to or different from each other,     -   L₁ and L₂ in Formula 1 may be different from each other,     -   and *′ in Formula 2 each indicate a binding site to M in Formula         1,     -   in Formula 2, Y₉ may be carbon, and a bond between N and Y₉ in         CY₁ may be a single bond or a double bond,     -   CY₁ in Formula 2 may be a benzoquinoline group or a         benzoisoquinoline group,     -   X₁ in Formula 2 may be O, S, S(═O)₂, Se, or N(R₂₁),     -   in Formula 2, Y₁ may be N, C(R₁), carbon bonded to Y₉, or carbon         bonded to M, Y₂ may be N, C(R₂), carbon bonded to Y₉, or carbon         bonded to M, Y₃ may be N, C(R₃), carbon bonded to Y₉, or carbon         bonded to M, Y₄ may be N, C(R₄), carbon bonded to Y₉, or carbon         bonded to M, Y₅ may be N or C(R₅), Y₆ may be N or C(R₆), Y₇ may         be N or C(R₇), Y₈ may be N or C(R₈), and one of Y₁ to Y₄ may be         carbon bonded to Y₉ while another of Y₁ to Y₄ may be carbon         bonded to M,     -   R₁ to R₈, R₁₀, and R₂₁ may each independently be selected from         hydrogen, deuterium, —F, —Cl, —Br, —I, —SF₅, a hydroxyl group, a         cyano group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, a substituted or         unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted         C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀         alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy         group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a         substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a         substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a         substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or         unsubstituted C₆-C₆₀ aryloxy group, a substituted or         unsubstituted C₆-C₆₀ arylthio group, a substituted or         unsubstituted C₇-C₆₀ arylalkyl group, a substituted or         unsubstituted C₁-C₆₀ heteroaryl group, a substituted or         unsubstituted C₁-C₆₀ heteroaryloxy group, a substituted or         unsubstituted C₁-C₆₀ heteroarylthio group, a substituted or         unsubstituted C₂-C₆₀ heteroarylalkyl group, a substituted or         unsubstituted monovalent non-aromatic condensed polycyclic         group, a substituted or unsubstituted monovalent non-aromatic         condensed heteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅),         —Ge(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), —P(═O)(Q₈)(Q₉), and —P(Q₈)(Q),     -   a10 may be an integer from 0 to 8,     -   two or more groups selected from R₁ to R₄ in Formula 2 may         optionally be linked to form a substituted or unsubstituted         C₅-C₃₀ carbocyclic group or a substituted or unsubstituted         C₂-C₃₀ heterocyclic group,     -   two or more groups selected from R₅ to R₈ in Formula 2 may         optionally be linked to form a substituted or unsubstituted         C₅-C₃₀ carbocyclic group or a substituted or unsubstituted         C₂-C₃₀ heterocyclic group,     -   two or more groups selected from a plurality of R₁₀ in Formula 2         may optionally be linked to form a substituted or unsubstituted         C₅-C₃₀ carbocyclic group or a substituted or unsubstituted         C₂-C₃₀ heterocyclic group,     -   at least one substituent of the substituted C₅-C₃₀ carbocyclic         group, the substituted C₂-C₃₀ heterocyclic group, the         substituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl         group, the substituted C₂-C₆₀ alkynyl group, the substituted         C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkyl group,         the substituted C₁-C₁₀ heterocycloalkyl group, the substituted         C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀         heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, the         substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀         arylthio group, the substituted C₇-C₆₀ arylalkyl group, the         substituted C₁-C₆₀ heteroaryl group, the substituted C₁-C₆₀         heteroaryloxy group, the substituted C₁-C₆₀ heteroarylthio         group, the substituted C₂-C₆₀ heteroarylalkyl group, the         substituted monovalent non-aromatic condensed polycyclic group,         and the substituted monovalent non-aromatic condensed         heteropolycyclic group may be selected from:     -   deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H,         —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino         group, an amidino group, a hydrazine group, a hydrazone group, a         carboxylic acid group or a salt thereof, a sulfonic acid group         or a salt thereof, a phosphoric acid group or a salt thereof, a         C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl         group, and a C₁-C₆₀ alkoxy group;     -   a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl         group, and a C₁-C₆₀ alkoxy group, each substituted with at least         one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H,         —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a         nitro group, an amino group, an amidino group, a hydrazine         group, a hydrazone group, a carboxylic acid group or a salt         thereof, a sulfonic acid group or a salt thereof, a phosphoric         acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a         C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a         C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀         aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl         group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group,         a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a         monovalent non-aromatic condensed polycyclic group, a monovalent         non-aromatic condensed heteropolycyclic group, —N(Q₁₁)(Q₁₂),         —Si(Q₁₃)(Q₁₄)(Q₁₅), —Ge(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇),         —P(═O)(Q₁₈)(Q₁₉), and —P(Q₁₈)(Q₁₉);     -   a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a         C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a         C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio         group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a         C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a         C₂-C₆₀ heteroarylalkyl group, a monovalent non-aromatic         condensed polycyclic group, and a monovalent non-aromatic         condensed heteropolycyclic group;     -   a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a         C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a         C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio         group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a         C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a         C₂-C₆₀ heteroarylalkyl group, a monovalent non-aromatic         condensed polycyclic group, and a monovalent non-aromatic         condensed heteropolycyclic group, each substituted with at least         one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H,         —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a         nitro group, an amino group, an amidino group, a hydrazine         group, a hydrazone group, a carboxylic acid group or a salt         thereof, a sulfonic acid group or a salt thereof, a phosphoric         acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀         alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a         C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a         C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a         C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio         group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a         C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a         C₂-C₆₀ heteroarylalkyl group, a monovalent non-aromatic         condensed polycyclic group, a monovalent non-aromatic condensed         heteropolycyclic group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅),         —Ge(Q₂₃)(Q₂₄)(Q₂₅), —B(Q₂₆)(Q₂₇), —P(═O)(Q₂₈)(Q₂₉), and         —P(Q₂₈)(Q₂₉); and     -   —N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —Ge(Q₃₃)(Q₃₄)(Q₃₅),         —B(Q₃₆)(Q₃₇), —P(═O)(Q₃₈)(Q₃₉), and —P(Q₃₈)(Q₃₉), and     -   Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ may each         independently be selected from hydrogen, deuterium, —F, —Cl,         —Br, —I, a hydroxyl group, a cyano group, a nitro group, an         amino group, an amidino group, a hydrazine group, a hydrazone         group, a carboxylic acid group or a salt thereof, a sulfonic         acid group or a salt thereof, a phosphoric acid group or a salt         thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀         alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group,         a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a         C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀         aryl group substituted with at least one selected from a C₁-C₆₀         alkyl group and a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a         C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀         heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀         heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a         monovalent non-aromatic condensed polycyclic group, and a         monovalent non-aromatic condensed heteropolycyclic group.

According to one or more embodiments, an organic light-emitting device includes:

-   -   a first electrode;     -   a second electrode; and     -   an organic layer disposed between the first electrode and the         second electrode,     -   wherein the organic layer includes an emission layer and at         least one organometallic compound described above.

The organometallic compound may act as a dopant in the organic layer.

BRIEF DESCRIPTION OF THE DRAWING

These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the FIGURE, which is a schematic view of an organic light-emitting device according to an embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

It will be understood that when an element is referred to as being “on” another element, it can be directly in contact with the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present.

It will be understood that, although the terms first, second, third etc. may be used herein to describe various elements, components, regions, layers, and/or sections, these elements, components, regions, layers, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the present embodiments.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

The term “or” means “and/or.” It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this general inventive concept belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to cross section illustrations that are schematic illustrations of idealized embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments described herein should not be construed as limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, a region illustrated or described as flat may, typically, have rough and/or nonlinear features. Moreover, sharp angles that are illustrated may be rounded. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the present claims.

“About” or “approximately” as used herein is inclusive of the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the particular quantity (i.e., the limitations of the measurement system). For example, “about” can mean within one or more standard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

An organometallic compound according to an embodiment is represented by Formula 1 below: M(L₁)_(n1)(L₂)_(n2)  Formula 1

M in Formula 1 may be selected from iridium (Ir), platinum (Pt), osmium (Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), thulium (Tm), rhodium (Rh), ruthenium (Ru), and rhenium (Re).

For example, M in Formula 1 may be iridium, platinum, or osmium, but embodiments of the present disclosure are not limited thereto.

In Formula 1, L₁ may be a ligand represented by Formula 2 described below, and n1 may be 1, 2, or 3, wherein, when n1 is two or more, two or more groups L₁ may be identical to or different from each other. Formula 2 is the same as described below. In an embodiment, n1 may be 2, but embodiments of the present disclosure are not limited thereto.

In Formula 1, L₂ may be selected from a monovalent organic ligand, a divalent organic ligand, a trivalent organic ligand, and a tetravalent organic ligand, and n2 may be 0, 1, 2, 3, or 4, wherein, when n2 is two or more, two or more groups L₂ may be identical to or different from each other.

L₁ and L₂ in Formula 1 may be different from each other.

* and *′ in Formula 2 each indicate a binding site to M in Formula 1.

For example, in Formula 1,

-   -   M may be Ir or Os, and the sum of n1 and n2 may be 3 or 4; or     -   M may be Pt, and the sum of n1 and n2 may be 2, but embodiments         of the present disclosure are not limited thereto.

In an embodiment, in Formula 1,

-   -   M may be Ir, n1 may be 2, and n2 may be 1;     -   M may be Os, n1 may be 2, and n2 may be 2; or     -   M may be Pt, n1 may be 2, and n2 may be 0, but embodiments of         the present disclosure are not limited thereto.

In Formula 2, Y₉ may be carbon, and a bond between N and Y₉ in CY₁ may be a single bond or a double bond.

CY₁ in Formula 2 may be a benzoquinoline group or a benzoisoquinoline group.

X₁ in Formula 2 may be O, S, S(═O)₂, Se, or N(R₂₁).

In an embodiment, X₁ in Formula 2 may be O or S, but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, X₁ in Formula 2 may be O, but embodiments of the present disclosure are not limited thereto.

In Formula 2, Y₁ may be N, C(R₁), carbon bonded to Y₉, or carbon bonded to M, Y₂ may be N, C(R₂), carbon bonded to Y₉, or carbon bonded to M, Y₃ may be N, C(R₃), carbon bonded to Y₉, or carbon bonded to M, Y₄ may be N, C(R₄), carbon bonded to Y₉, or carbon bonded to M, Y₅ may be N or C(R₅), Y₆ may be N or C(R₆), Y₇ may be N or C(R₇), Y₈ may be N or C(R₈), and one of Y₁ to Y₄ may be carbon bonded to Y₉ while another of Y₁ to Y₄ may be carbon bonded to M.

In one or more embodiments, all of Y₁ to Y₈ in Formula 2 may not be N.

In one or more embodiments, at least one of Y₅ to Y₈ in Formula 2 may be N.

In one or more embodiments, in Formula 2, Y₅ may be C(R₅), Y₆ may be C(R₆), Y₇ may be C(R₇), and Y₈ may be N or C(R₈), but embodiments of the present disclosure are not limited thereto.

R₁ to R₈, R₁₀, and R₂₁ in Formula 2 may each independently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, —SF₅, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₇-C₆₀ arylalkyl group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted C₁-C₆₀ heteroaryloxy group, a substituted or unsubstituted C₁-C₆₀ heteroarylthio group, a substituted or unsubstituted C₂-C₆₀ heteroarylalkyl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —Ge(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), —P(═O)(Q₈)(Q), and —P(Q₈)(Q₀). Q₁ to Q₉ are each independently the same as described herein.

For example, R₁ to R₈, R₁₀, and R₂₁ in Formula 2 may each independently be selected from:

-   -   hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano         group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, —SF₅, a C₁-C₂₀ alkyl         group, and a C₁-C₂₀ alkoxy group;     -   a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted         with at least one selected from deuterium, —F, —Cl, —Br, —I,         —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a         cyano group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, a C₁-C₁₀ alkyl group, a         cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a         cyclooctyl group, an adamantanyl group, a norbornanyl group, a         norbornenyl group, a cyclopentenyl group, a cyclohexenyl group,         a cycloheptenyl group, a bicyclo[2.2.2]octyl group, a phenyl         group, a naphthyl group, a pyridinyl group, and a pyrimidinyl         group;     -   a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a         cyclooctyl group, an adamantanyl group, a norbornanyl group, a         norbornenyl group, a cyclopentenyl group, a cyclohexenyl group,         a cycloheptenyl group, a bicyclo[2.2.2]octyl group, a phenyl         group, a naphthyl group, a fluorenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         pyrrolyl group, a thiophenyl group, a furanyl group, an         imidazolyl group, a pyrazolyl group, a thiazolyl group, an         isothiazolyl group, an oxazolyl group, an isoxazolyl group, a         pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a         pyridazinyl group, an isoindolyl group, an indolyl group, an         indazolyl group, a purinyl group, a quinolinyl group, an         isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl         group, a quinazolinyl group, a cinnolinyl group, a carbazolyl         group, a phenanthrolinyl group, a benzimidazolyl group, a         benzofuranyl group, a benzothiophenyl group, an         isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a         dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, an imidazopyridinyl group, and an         imidazopyrimidinyl group;     -   a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a         cyclooctyl group, an adamantanyl group, a norbornanyl group, a         norbornenyl group, a cyclopentenyl group, a cyclohexenyl group,         a cycloheptenyl group, a bicyclo[2.2.2]octyl group, a phenyl         group, a naphthyl group, a fluorenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         pyrrolyl group, a thiophenyl group, a furanyl group, an         imidazolyl group, a pyrazolyl group, a thiazolyl group, an         isothiazolyl group, an oxazolyl group, an isoxazolyl group, a         pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a         pyridazinyl group, an isoindolyl group, an indolyl group, an         indazolyl group, a purinyl group, a quinolinyl group, an         isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl         group, a quinazolinyl group, a cinnolinyl group, a carbazolyl         group, a phenanthrolinyl group, a benzimidazolyl group, a         benzofuranyl group, a benzothiophenyl group, an         isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a         dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, an imidazopyridinyl group, and an         imidazopyrimidinyl group, each substituted with at least one         selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂,         —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro         group, an amino group, an amidino group, a hydrazine group, a         hydrazone group, a carboxylic acid group or a salt thereof, a         sulfonic acid group or a salt thereof, a phosphoric acid group         or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group,         a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a         cyclooctyl group, an adamantanyl group, a norbornanyl group, a         norbornenyl group, a cyclopentenyl group, a cyclohexenyl group,         a cycloheptenyl group, a bicyclo[2.2.2]octyl group, a phenyl         group, a naphthyl group, a fluorenyl group, a phenanthrenyl         group, an anthracenyl group, a fluoranthenyl group, a         triphenylenyl group, a pyrenyl group, a chrysenyl group, a         pyrrolyl group, a thiophenyl group, a furanyl group, an         imidazolyl group, a pyrazolyl group, a thiazolyl group, an         isothiazolyl group, an oxazolyl group, an isoxazolyl group, a         pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a         pyridazinyl group, an isoindolyl group, an indolyl group, an         indazolyl group, a purinyl group, a quinolinyl group, an         isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl         group, a quinazolinyl group, a cinnolinyl group, a carbazolyl         group, a phenanthrolinyl group, a benzimidazolyl group, a         benzofuranyl group, a benzothiophenyl group, an         isobenzothiazolyl group, a benzoxazolyl group, an         isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an         oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a         dibenzothiophenyl group, a benzocarbazolyl group, a         dibenzocarbazolyl group, an imidazopyridinyl group, an         imidazopyrimidinyl group, and —Si(Q₃₃)(Q₃₄)(Q₃₅); and     -   —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —Ge(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇),         —P(═O)(Q₈)(Q), and —P(Q₈)(Q), and     -   Q₁ to Q₉ and Q₃₃ to Q₃₅ may each independently be selected from:     -   —CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂,         —CHDCH₃, —CHDCD₂H, —CHDCDH₂, —CHDCD₃, —CD₂CD₃, —CD₂CD₂H, and         —CD₂CDH₂;     -   an n-propyl group, an iso-propyl group, an n-butyl group, an         iso-butyl group, a sec-butyl group, a tert-butyl group, an         n-pentyl group, an iso-pentyl group, a sec-pentyl group, a         tert-pentyl group, a phenyl group, and a naphthyl group; and     -   an n-propyl group, an iso-propyl group, an n-butyl group, an         iso-butyl group, a sec-butyl group, a tert-butyl group, an         n-pentyl group, an iso-pentyl group, a sec-pentyl group, a         tert-pentyl group, a phenyl group, and a naphthyl group, each         substituted with at least one selected from deuterium, a C₁-C₁₀         alkyl group, and a phenyl group.

In an embodiment, R₁ to R₈, R₁₀, and R₂₁ in Formula 2 may each independently be selected from:

-   -   hydrogen, deuterium, —F, a cyano group, a nitro group, —SF₅, a         methyl group, an ethyl group, an n-propyl group, an iso-propyl         group, an n-butyl group, an iso-butyl group, a sec-butyl group,         a tert-butyl group, an n-pentyl group, an iso-pentyl group, a         sec-pentyl group, a tert-pentyl group, an n-hexyl group, an         iso-hexyl group, a sec-hexyl group, a tert-hexyl group, an         n-heptyl group, an iso-heptyl group, a sec-heptyl group, a         tert-heptyl group, an n-octyl group, an iso-octyl group, a         sec-octyl group, a tert-octyl group, an n-nonyl group, an         iso-nonyl group, a sec-nonyl group, a tert-nonyl group, an         n-decyl group, an iso-decyl group, a sec-decyl group, a         tert-decyl group, a methoxy group, an ethoxy group, a propoxy         group, a butoxy group, a pentoxy group, a cyclopentyl group, a         cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an         adamantanyl group, a norbornanyl group, a norbornenyl group, a         cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl         group, a bicyclo[2.2.2]octyl group, a phenyl group, a naphthyl         group, a pyridinyl group, a pyrimidinyl group, a dibenzofuranyl         group, and a dibenzothiophenyl group;     -   a methyl group, an ethyl group, an n-propyl group, an iso-propyl         group, an n-butyl group, an iso-butyl group, a sec-butyl group,         a tert-butyl group, an n-pentyl group, an iso-pentyl group, a         sec-pentyl group, a tert-pentyl group, an n-hexyl group, an         iso-hexyl group, a sec-hexyl group, a tert-hexyl group, an         n-heptyl group, an iso-heptyl group, a sec-heptyl group, a         tert-heptyl group, an n-octyl group, an iso-octyl group, a         sec-octyl group, a tert-octyl group, an n-nonyl group, an         iso-nonyl group, a sec-nonyl group, a tert-nonyl group, an         n-decyl group, an iso-decyl group, a sec-decyl group, a         tert-decyl group, a methoxy group, an ethoxy group, a propoxy         group, a butoxy group, a pentoxy group, a cyclopentyl group, a         cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an         adamantanyl group, a norbornanyl group, a norbornenyl group, a         cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl         group, a bicyclo[2.2.2]octyl group, a phenyl group, a naphthyl         group, a pyridinyl group, a pyrimidinyl group, a dibenzofuranyl         group, and a dibenzothiophenyl group, each substituted with at         least one selected from deuterium, —F, —CD₃, —CD₂H, —CDH₂, —CF₃,         —CF₂H, —CFH₂, a cyano group, a nitro group, a C₁-C₁₀ alkyl         group, a C₁-C₁₀ alkoxy group, a cyclopentyl group, a cyclohexyl         group, a cycloheptyl group, a cyclooctyl group, an adamantanyl         group, a norbornanyl group, a norbornenyl group, a cyclopentenyl         group, a cyclohexenyl group, a cycloheptenyl group, a         bicyclo[2.2.2]octyl group, a phenyl group, a naphthyl group, a         pyridinyl group, a pyrimidinyl group, a dibenzofuranyl group,         and a dibenzothiophenyl group; and     -   —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —Ge(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇),         —P(═O)(Q₈)(Q), and —P(Q₈)(Q), and     -   Q₁ to Q₉ may each independently be selected from:     -   —CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂,         —CHDCH₃, —CHDCD₂H, —CHDCDH₂, —CHDCD₃, —CD₂CD₃, —CD₂CD₂H, and         —CD₂CDH₂;     -   an n-propyl group, an iso-propyl group, an n-butyl group, an         iso-butyl group, a sec-butyl group, a tert-butyl group, an         n-pentyl group, an iso-pentyl group, a sec-pentyl group, a         tert-pentyl group, a phenyl group, and a naphthyl group; and     -   an n-propyl group, an iso-propyl group, an n-butyl group, an         iso-butyl group, a sec-butyl group, a tert-butyl group, an         n-pentyl group, an iso-pentyl group, a sec-pentyl group, a         tert-pentyl group, a phenyl group, and a naphthyl group, each         substituted with at least one selected from deuterium, a C₁-C₁₀         alkyl group, and a phenyl group.

In one or more embodiments, R₁ to R₈, R₁₀, and R₂₁ in Formula 2 may each independently be selected from hydrogen, deuterium, —F, a cyano group, a nitro group, —SF₅, —CH₃, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, groups represented by Formulae 9-1 to 9-20, groups represented by Formulae 10-1 to 10-142, —Si(Q₃)(Q₄)(Q₅), and —Ge(Q₃)(Q₄)(Q₅), and

-   -   Q₃ to Q₅ may each independently be selected from:     -   —CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂,         —CHDCH₃, —CHDCD₂H, —CHDCDH₂, —CHDCD₃, —CD₂CD₃, —CD₂CD₂H, and         —CD₂CDH₂;     -   an n-propyl group, an iso-propyl group, an n-butyl group, an         iso-butyl group, a sec-butyl group, a tert-butyl group, an         n-pentyl group, an iso-pentyl group, a sec-pentyl group, a         tert-pentyl group, a phenyl group, and a naphthyl group; and     -   an n-propyl group, an iso-propyl group, an n-butyl group, an         iso-butyl group, a sec-butyl group, a tert-butyl group, an         n-pentyl group, an iso-pentyl group, a sec-pentyl group, a         tert-pentyl group, a phenyl group, and a naphthyl group, each         substituted with at least one selected from deuterium, a C₁-C₁₀         alkyl group, and a phenyl group:

In Formulae 9-1 to 9-20 and 10-1 to 10-142, “Ph” indicates a phenyl group, “TMS” indicates a trimethylsilyl group, and * indicates a binding site to a neighboring atom.

a10 in Formula 2 indicates the number of groups R₁₀ and may be an integer from 0 to 8. When a10 is two or more, two or more groups R₁₀ may be identical to or different from each other.

In an embodiment, a10 in Formula 2 may be 0, 1, or 2, or may be 0 or 1, but embodiments of the present disclosure are not limited thereto.

Two or more groups selected from R₁ to R₄ in Formula 2 may optionally be linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₂-C₃₀ heterocyclic group, two or more groups selected from R₅ to R₈ in Formula 2 may optionally be linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₂-C₃₀ heterocyclic group, and two or more groups selected from a plurality of R₁₀ in Formula 2 may optionally be linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₂-C₃₀ heterocyclic group.

For example, i) a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₂-C₃₀ heterocyclic group, formed by linking two of R₁ to R₄, ii) a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₂-C₃₀ heterocyclic group, formed by linking two of R₅ to R₈, and iii) a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₂-C₃₀ heterocyclic group, formed by linking two of a plurality of R₁₀, in Formula 2, may each independently be selected from:

-   -   a pentadiene group, a cyclohexane group, a cycloheptane group,         an adamantane group, a bicycloheptane group, a bicyclo-octane         group, a benzene group, a pyridine group, a pyrimidine group, a         pyrazine group, a pyridazine group, a naphthalene group, an         anthracene group, a tetracene group, a phenanthrene group, a         dihydronaphthalene group, a phenalene group, a benzofuran group,         a benzothiophene group, a benzoselenophene group, an indole         group, an indene group, a benzosilole group, an azabenzofuran         group, an azabenzothiophene group, an azabenzoselenophene group,         an azaindole group, an azaindene group, and an azabenzosilole         group; and     -   a pentadiene group, a cyclohexane group, a cycloheptane group,         an adamantane group, a bicycloheptane group, a bicyclo-octane         group, a benzene group, a pyridine group, a pyrimidine group, a         pyrazine group, a pyridazine group, a naphthalene group, an         anthracene group, a tetracene group, a phenanthrene group, a         dihydronaphthalene group, a phenalene group, a benzofuran group,         a benzothiophene group, a benzoselenophene group, an indole         group, an indene group, a benzosilole group, an azabenzofuran         group, an azabenzothiophene group, an azabenzoselenophene group,         an azaindole group, an azaindene group, and an azabenzosilole         group, each substituted with at least one R_(10a),     -   but embodiments of the present disclosure are not limited         thereto.

R_(10a) is the same as described in connection with R₁₀.

In one or more embodiments,

-   -   a moiety represented by

in Formula 2 may be selected from groups represented by Formulae CY1-1 to CY1-9, but embodiments of the present disclosure are not limited thereto:

In Formulae CY1-1 to CY1-9, R₁₁ to R₁₈ are each independently the same as described in connection with R₁₀, and * indicates a binding site to M in Formula 1.

In one or more embodiments, a moiety represented by

in Formula 2 may be a group represented by Formula CY1-1.

In one or more embodiments, a moiety represented by

in Formula 2 may be a group represented by Formula CY1-1, and R₁₁ in Formula CY1-1 may not be hydrogen, but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, L₁ in Formula 1 may be selected from ligands represented by Formulae 2-1 to 2-6:

CY₁, X₁, Y₁ to Y₉, R₁₀, a10, *, and *′ in Formulae 2-1 to 2-6 are each independently the same as described herein.

In one or more embodiments, L₁ in Formula 1 may be a ligand represented by Formula 2A:

In Formula 2A,

-   -   Y₈ may be N or C(R₈),     -   X₁, R₃ to R₈, *, and *′ are each independently the same as         described herein, and     -   R₁₁ to R₁₈ are each independently the same as described in         connection with R₁₀.

For example, in Formula 2A, R₃ and R₄ may optionally be linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₂-C₃₀ heterocyclic group, and two or more groups selected from R₅ to R₈ may optionally be linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₂-C₃₀ heterocyclic group.

For example, i) a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₂-C₃₀ heterocyclic group, formed by linking R₃ and R₄, and ii) a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₂-C₃₀ heterocyclic group, formed by linking two of R₅ to R₈, in Formula 2A, may each independently be selected from:

-   -   a pentadiene group, a cyclohexane group, a cycloheptane group,         an adamantane group, a bicycloheptane group, a bicyclo-octane         group, a benzene group, a pyridine group, a pyrimidine group, a         pyrazine group, a pyridazine group, a naphthalene group, an         anthracene group, a tetracene group, a phenanthrene group, a         dihydronaphthalene group, a phenalene group, a benzofuran group,         a benzothiophene group, a benzoselenophene group, an indole         group, an indene group, a benzosilole group, an azabenzofuran         group, an azabenzothiophene group, an azabenzoselenophene group,         an azaindole group, an azaindene group, and an azabenzosilole         group; and     -   a pentadiene group, a cyclohexane group, a cycloheptane group,         an adamantane group, a bicycloheptane group, a bicyclo-octane         group, a benzene group, a pyridine group, a pyrimidine group, a         pyrazine group, a pyridazine group, a naphthalene group, an         anthracene group, a tetracene group, a phenanthrene group, a         dihydronaphthalene group, a phenalene group, a benzofuran group,         a benzothiophene group, a benzoselenophene group, an indole         group, an indene group, a benzosilole group, an azabenzofuran         group, an azabenzothiophene group, an azabenzoselenophene group,         an azaindole group, an azaindene group, and an azabenzosilole         group, each substituted with at least one R_(10a),     -   but embodiments of the present disclosure are not limited         thereto.

R_(10a) is the same as described in connection with R₁₀.

In an embodiment, at least one of R₃ and R₁ in Formula 2A may not be hydrogen.

In one or more embodiments, R₄ to R₈ and R₁₂ to R₁₈ in Formula 2A may each be hydrogen.

In one or more embodiments, R₃ to R₈ and R₁₁ to R₁₈ in Formula 2A may each be hydrogen.

In one or more embodiments, L₂ in Formula 1 may be selected from ligands represented by Formulae 3A to 3F:

In Formulae 3A to 3F,

-   -   Y₁₁ may be selected from O, N, N(Z₁), P(Z₁)(Z₂), and As(Z₁)(Z₂),     -   Y₁₂ may be selected from O, N, N(Z₃), P(Z₃)(Z₄), and As(Z₃)(Z₄),     -   T₁₁ may be selected from a single bond, a double bond,         *—C(Z₁₁)(Z₁₂)—*′, *—C(Z₁₁)═C(Z₁₂)—*′, *═C(Z₁₁)—*′, *—C(Z₁₁)═*′,         *═C(Z₁₁)—C(Z₁₂)═C(Z₁₃)—*′, *—C(Z₁₁)═C(Z₁₂)—C(Z₁₃)═*′,         *—N(Z₁₁)—*′, and a substituted or unsubstituted C₆-C₃₀ arylene         group,     -   a11 may be an integer from 1 to 5,     -   Y₁₃ to Y₁₆ may each independently be carbon (C) or nitrogen (N),         a bond between Y₁₃ and Y₁₄ may be a single bond or a double         bond, and a bond between Y₁₅ and Y₁₆ may be a single bond or a         double bond,     -   CY₁₁ to CY₁₃ may each independently be a C₅-C₃₀ carbocyclic         group or a C₂-C₃₀ heterocyclic group,     -   A₁ may be P or As,     -   Z₁ to Z₄ and Z₁₁ to Z₁₃ are each independently the same as         described in connection with R₁₀,     -   d1 and d2 may each independently be an integer from 0 to 10, and     -   and *′ each indicate a binding site to M in Formula 1.

For example, CY₁₁ to CY₁₃ in Formulae 3A to 3F may each independently be selected from a benzene group, a naphthalene group, a pyridine group, a pyrimidine group, a triazine group, a pyrrole group, a pyrazole group, an imidazole group, and a triazole group.

In an embodiment, L₂ in Formula 1 may be selected from ligands represented by Formulae 3-1 to 3-15, but embodiments of the present disclosure are not limited thereto:

In Formulae 3-1 to 3-15,

-   -   X₃₁ may be N or C(Z_(1a)), and X₃₂ may be N or C(Z_(1b)),     -   X₄₁ may be O, S, N(Z_(1c)), or C(Z_(1d))(Z_(1e)),     -   Z₁ to Z₄, Z_(1a) to Z_(1e), and Z₁₁ to Z₁₄ are each         independently the same as described in connection with R₁₀,     -   e2 may be an integer from 0 to 2,     -   e3 may be an integer from 0 to 3,     -   e4 may be an integer from 0 to 4, and     -   and *′ each indicate a binding site to M in Formula 1.

For example, Z₁ to Z₄, Z_(1a) to Z_(1e), and Z₁₁ to Z₁₄ in Formulae 3-1 to 3-15 may each independently be selected from hydrogen, deuterium, —F, a cyano group, a nitro group, —SF₅, —CH₃, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, groups represented by Formulae 9-1 to 9-20, groups represented by Formulae 10-1 to 10-142, —Si(Q₃)(Q₄)(Q₅), and —Ge(Q₃)(Q₄)(Q₅), but embodiments of the present disclosure are not limited thereto.

In an embodiment, in Formula 1, L₁ may be a ligand represented by Formula 2, that is, a group in which a moiety represented by

is a group represented by one of Formulae CY1-1 to CY₁-3 (for example, a group represented by Formula CY1-1), and L₂ may be selected from ligands represented by Formulae 3A to 3F (for example, ligands represented by Formulae 3-1 to 3-15).

In one or more embodiments, in Formula 1, L₁ may be a ligand represented by Formula 2-1 (for example, a ligand represented by Formula 2A), and L₂ may be selected from ligands represented by Formulae 3A to 3F (for example, ligands represented by Formulae 3-1 to 3-15).

In one or more embodiments, in Formula 1,

-   -   M may be Ir or Os, and the sum of n1 and n2 may be 3 or 4; or M         may be Pt, and the sum of n1 and n2 may be 2,     -   L₁ may be a ligand represented by Formula 2A,         L₂ may be selected from ligands represented by Formulae 3A to 3F         (for example, ligands represented by Formulae 3-1 to 3-15), but         embodiments of the present disclosure are not limited thereto.

The organometallic compound may be one of Compounds 1 to 144, but embodiments of the present disclosure are not limited thereto:

^(i)Bu in Compounds 1 to 144 indicates an iso-butyl group.

L₁ in the organometallic compound represented by Formula 1 may be a ligand represented by Formula 2, and X₁ in Formula 2 may be O, S, S(═O)₂, Se, or N(R₂₁).

By employing O, S, S(═O)₂, Se, or N(R₂₁) having high electronegativity as X₁ in Formula 2, as described above, the organometallic compound represented by Formula 1 may have a relatively low highest occupied molecular orbital (HOMO) energy level (that is, a relatively large absolute value of a HOMO energy level), and thus, the organometallic compound may have excellent oxidation stability. Therefore, an electronic device, for example, an organic light-emitting device, which includes the organometallic compound, may have a low driving voltage.

Also, CY₁ in Formula 2 may be a benzoquinoline group or a benzoisoquinoline group having a long conjugation length. Accordingly, the organometallic compound represented by Formula 1 may have improved durability and may also have excellent electron injection characteristics due to a low lowest unoccupied molecular orbital (LUMO) energy level (that is, a relatively large absolute value of a LUMO energy level).

For example, HOMO, LUMO, and triplet (Ti) energy levels of some of the organometallic compounds were evaluated by using a density functional theory (DFT) method of a Gaussian program (structurally optimized at a B3LYP/6-31G(d,p) level). Evaluation results thereof are shown in Table 1.

TABLE 1 Compound HOMO LUMO T₁ energy level No. (eV) (eV) (eV) Compound 1 −4.791 −1.791 2.160 Compound 2 −4.748 −1.797 2.143 Compound 3 −4.730 −1.693 2.212 Compound 4 −4.764 −1.849 2.090 Compound 5 −4.748 −1.797 2.122 Compound 6 −4.728 −1.851 2.080 Compound 7 −4.710 −1.843 2.063 Compound 8 −4.735 −1.878 2.046

From Table 1, it has been determined that the organometallic compound represented by Formula 1 has such electrical characteristics that are suitable for use in an electronic device, for example, for use as a dopant for an organic light-emitting device.

Synthesis methods of the organometallic compound represented by Formula 1 may be recognizable by those of ordinary skill in the art by referring to Synthesis Examples provided below.

The organometallic compound represented by Formula 1 is suitable for use in an organic layer of an organic light-emitting device, for example, for use as a dopant in an emission layer of the organic layer. Thus, another aspect provides an organic light-emitting device that includes:

-   -   a first electrode;     -   a second electrode; and     -   an organic layer that is disposed between the first electrode         and the second electrode,     -   wherein the organic layer includes an emission layer and at         least one organometallic compound represented by Formula 1.

The organic light-emitting device may have, due to the inclusion of an organic layer including the organometallic compound represented by Formula 1, a low driving voltage, high luminescent efficiency, high power efficiency, high quantum efficiency, a long lifespan, a low roll-off ratio, and excellent color purity.

The organometallic compound represented by Formula 1 may be used between a pair of electrodes of an organic light-emitting device. For example, the organometallic compound represented by Formula 1 may be included in the emission layer. In this embodiment, the organometallic compound may act as a dopant, and the emission layer may further include a host (that is, in the emission layer, an amount of the organometallic compound represented by Formula 1 is smaller than an amount of the host).

The expression “(an organic layer) includes at least one of organometallic compounds” as used herein may include an embodiment in which “(an organic layer) includes identical organometallic compounds represented by Formula 1” and an embodiment in which “(an organic layer) includes two or more different organometallic compounds represented by Formula 1.”

For example, the organic layer may include, as the organometallic compound, only Compound 1. In this embodiment, Compound 1 may be included in an emission layer of the organic light-emitting device. In one or more embodiments, the organic layer may include, as the organometallic compound, Compound 1 and Compound 2. In this embodiment, Compound 1 and Compound 2 may be included in an identical layer (for example, Compound 1 and Compound 2 may both be included in an emission layer).

The first electrode may be an anode, which is a hole injection electrode, and the second electrode may be a cathode, which is an electron injection electrode; or the first electrode may be a cathode, which is an electron injection electrode, and the second electrode may be an anode, which is a hole injection electrode.

In an embodiment, in the organic light-emitting device, the first electrode is an anode, and the second electrode is a cathode, and the organic layer further includes a hole transport region disposed between the first electrode and the emission layer and an electron transport region disposed between the emission layer and the second electrode, wherein the hole transport region includes a hole injection layer, a hole transport layer, an electron blocking layer, or any combination thereof, and wherein the electron transport region includes a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.

The term “organic layer” as used herein refers to a single layer and/or a plurality of layers disposed between the first electrode and the second electrode of the organic light-emitting device. The “organic layer” may include, in addition to an organic compound, an organometallic complex including metal.

The FIG. 1 s a schematic view of an organic light-emitting device 10 according to an embodiment. Hereinafter, the structure of an organic light-emitting device according to an embodiment and a method of manufacturing an organic light-emitting device according to an embodiment will be described in connection with the FIGURE. The organic light-emitting device 10 includes a first electrode 11, an organic layer 15, and a second electrode 19, which are sequentially stacked.

A substrate may be additionally disposed under the first electrode 11 or above the second electrode 19. For use as the substrate, any substrate that is used in general organic light-emitting devices may be used, and the substrate may be a glass substrate or a transparent plastic substrate, each having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and water resistance.

The first electrode 11 may be formed by depositing or sputtering a material for forming the first electrode 11 on the substrate. The first electrode 11 may be an anode. The material for forming the first electrode 11 may be selected from materials with a high work function to facilitate hole injection. The first electrode 11 may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode. The material for forming the first electrode may be, for example, indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO₂), and zinc oxide (ZnO). In one or more embodiments, magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), or magnesium-silver (Mg—Ag) may be used as the material for forming the first electrode.

The first electrode 11 may have a single-layered structure or a multi-layered structure including two or more layers. For example, the first electrode 11 may have a three-layered structure of ITO/Ag/ITO, but the structure of the first electrode 110 is not limited thereto.

The organic layer 15 is disposed on the first electrode 11.

The organic layer 15 may include a hole transport region, an emission layer, and an electron transport region.

The hole transport region may be disposed between the first electrode 11 and the emission layer.

The hole transport region may include a hole injection layer, a hole transport layer, an electron blocking layer, a buffer layer, or any combination thereof.

The hole transport region may include only either a hole injection layer or a hole transport layer. In one or more embodiments, the hole transport region may have a hole injection layer/hole transport layer structure or a hole injection layer/hole transport layer/electron blocking layer structure, which are sequentially stacked in this stated order from the first electrode 11.

A hole injection layer may be formed on the first electrode 11 by using one or more suitable methods selected from vacuum deposition, spin coating, casting, or Langmuir-Blodgett (LB) deposition.

When a hole injection layer is formed by vacuum deposition, the deposition conditions may vary depending on a compound that is used to form the hole injection layer, and the structure and thermal characteristics of the hole injection layer. For example, the deposition conditions may include a deposition temperature of about 100° C. to about 500° C., a vacuum pressure of about 10⁻⁸ torr to about 10⁻³ torr, and a deposition rate of about 0.01 Angstroms per second (Å/sec) to about 100 Å/sec. However, the deposition conditions are not limited thereto.

When the hole injection layer is formed using spin coating, coating conditions may vary according to the material used to form the hole injection layer, and the structure and thermal properties of the hole injection layer. For example, a coating speed may be from about 2,000 revolutions per minute (rpm) to about 5,000 rpm, and a temperature at which a heat treatment is performed to remove a solvent after coating may be from about 80° C. to about 200° C. However, the coating conditions are not limited thereto.

Conditions for forming a hole transport layer and an electron blocking layer may be understood by referring to conditions for forming the hole injection layer.

The hole transport region may include at least one selected from m-MTDATA, TDATA, 2-TNATA, NPB, β-NPB, TPD, Spiro-TPD, Spiro-NPB, methylated-NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA), polyaniline/dodecylbenzene sulfonic acid (PANI/DBSA), poly(3,4-ethylenedioxythiophene)/poly(4-styrene sulfonate) (PEDOT/PSS), polyaniline/camphor sulfonic acid (PANI/CSA), polyaniline/poly(4-styrene sulfonate) (PANI/PSS), a compound represented by Formula 201 below, and a compound represented by Formula 202 below:

Ar₁₀₁ and Ar₁₀₂ in Formula 201 may each independently be selected from:

-   -   a phenylene group, a pentalenylene group, an indenylene group, a         naphthylene group, an azulenylene group, a heptalenylene group,         an acenaphthylene group, a fluorenylene group, a phenalenylene         group, a phenanthrenylene group, an anthracenylene group, a         fluoranthenylene group, a triphenylenylene group, a pyrenylene         group, a chrysenylenylene group, a naphthacenylene group, a         picenylene group, a perylenylene group, and a pentacenylene         group; and     -   a phenylene group, a pentalenylene group, an indenylene group, a         naphthylene group, an azulenylene group, a heptalenylene group,         an acenaphthylene group, a fluorenylene group, a phenalenylene         group, a phenanthrenylene group, an anthracenylene group, a         fluoranthenylene group, a triphenylenylene group, a pyrenylene         group, a chrysenylenylene group, a naphthacenylene group, a         picenylene group, a perylenylene group, and a pentacenylene         group, each substituted with at least one selected from         deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a         nitro group, an amino group, an amidino group, a hydrazine         group, a hydrazone group, a carboxylic acid group or a salt         thereof, a sulfonic acid group or a salt thereof, a phosphoric         acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀         alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a         C₃-C₁₀ cycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀         heterocycloalkyl group, a C₁-C₁₀ heterocycloalkenyl group, a         C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio         group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a         C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a         C₂-C₆₀ heteroarylalkyl group, a monovalent non-aromatic         condensed polycyclic group, and a monovalent non-aromatic         condensed heteropolycyclic group.

xa and xb in Formula 201 may each independently be an integer from 0 to 5, or may each independently be 0, 1, or 2. For example, xa may be 1 and xb may be 0, but embodiments of the present disclosure are not limited thereto.

R₁₀₁ to R₁₀₈, R₁₁₁ to R₁₁₉, and R₁₂₁ to R₁₂₄ in Formulae 201 and 202 may each independently be selected from:

-   -   hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano         group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, a C₁-C₁₀ alkyl group         (for example, a methyl group, an ethyl group, a propyl group, a         butyl group, pentyl group, and a hexyl group), and a C₁-C₁₀         alkoxy group (for example, a methoxy group, an ethoxy group, a         propoxy group, a butoxy group, and a pentoxy group);     -   a C₁-C₁₀ alkyl group and a C₁-C₁₀ alkoxy group, each substituted         with at least one selected from deuterium, —F, —Cl, —Br, —I, a         hydroxyl group, a cyano group, a nitro group, an amino group, an         amidino group, a hydrazine group, a hydrazone group, a         carboxylic acid group or a salt thereof, a sulfonic acid group         or a salt thereof, and a phosphoric acid group or a salt         thereof;     -   a phenyl group, a naphthyl group, an anthracenyl group, a         fluorenyl group, and a pyrenyl group; and     -   a phenyl group, a naphthyl group, an anthracenyl group, a         fluorenyl group, and a pyrenyl group, each substituted with at         least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl         group, a cyano group, a nitro group, an amino group, an amidino         group, a hydrazine group, a hydrazone group, a carboxylic acid         group or a salt thereof, a sulfonic acid group or a salt         thereof, a phosphoric acid group or a salt thereof, a C₁-C₁₀         alkyl group, and a C₁-C₁₀ alkoxy group,     -   but embodiments of the present disclosure are not limited         thereto.

R₁₀₉ in Formula 201 may be selected from:

-   -   a phenyl group, a naphthyl group, an anthracenyl group, and a         pyridinyl group; and     -   a phenyl group, a naphthyl group, an anthracenyl group, and a         pyridinyl group, each substituted with at least one selected         from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano         group, a nitro group, an amino group, an amidino group, a         hydrazine group, a hydrazone group, a carboxylic acid group or a         salt thereof, a sulfonic acid group or a salt thereof, a         phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a         C₁-C₂₀ alkoxy group, a phenyl group, a naphthyl group, an         anthracenyl group, and a pyridinyl group.

According to an embodiment, the compound represented by Formula 201 may be represented by Formula 201A, but embodiments of the present disclosure are not limited thereto:

R₁₀₁, R₁₁₁, R₁₁₂, and R₁₀₉ in Formula 201A may be understood by referring to the description provided herein.

For example, the compound represented by Formula 201 and the compound represented by Formula 202 may include compounds HT1 to HT20 illustrated below, but embodiments of the present disclosure are not limited thereto:

A thickness of the hole transport region may be in a range of about 100 Å to about 10,000 Å, for example, about 100 Å to about 1,000 Å. When the hole transport region includes at least one of a hole injection layer and a hole transport layer, the thickness of the hole injection layer may be in a range of about 100 Å to about 10,000 Å, and for example, about 100 Å to about 1,000 Å, and the thickness of the hole transport layer may be in a range of about 50 Å to about 2,000 Å, and for example, about 100 Å to about 1,500 Å. While not wishing to be bound by theory, it is understood that when the thicknesses of the hole transport region, the hole injection layer, and the hole transport layer are within these ranges, satisfactory hole transporting characteristics may be obtained without a substantial increase in driving voltage.

The hole transport region may further include, in addition to these materials, a charge-generation material for the improvement of conductive properties. The charge-generation material may be homogeneously or non-homogeneously dispersed in the hole transport region.

The charge-generation material may be, for example, a p-dopant. The p-dopant may be one selected from a quinone derivative, a metal oxide, and a cyano group-containing compound, but embodiments of the present disclosure are not limited thereto. Non-limiting examples of the p-dopant are a quinone derivative, such as tetracyanoquinonedimethane (TCNQ) or 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinonedimethane (F4-TCNQ); a metal oxide, such as a tungsten oxide or a molybdenium oxide; and a cyano group-containing compound, such as Compound HT-D1 below, but are not limited thereto:

The hole transport region may include a buffer layer.

Also, the buffer layer may compensate for an optical resonance distance according to a wavelength of light emitted from the emission layer, and thus, efficiency of a formed organic light-emitting device may be improved.

Then, an emission layer may be formed on the hole transport region by vacuum deposition, spin coating, casting, LB deposition, or the like. When the emission layer is formed by vacuum deposition or spin coating, the deposition or coating conditions may be similar to those applied in forming the hole injection layer although the deposition or coating conditions may vary according to a compound that is used to form the emission layer.

Meanwhile, when the hole transport region includes an electron blocking layer, a material for the electron blocking layer may be selected from materials for the hole transport region described above and materials for a host to be explained later. However, the material for the electron blocking layer is not limited thereto. For example, when the hole transport region includes an electron blocking layer, a material for the electron blocking layer may be mCP, which will be explained later.

The emission layer may include a host and a dopant, and the dopant may include the organometallic compound represented by Formula 1.

The host may include at least one selected from TPBi, TBADN, ADN (also referred to as “DNA”), CBP, CDBP, TCP, mCP, Compound H50, and Compound H51:

In one or more embodiments, the host may further include a compound represented by Formula 301 below.

Ar₁₁₁ and Ar₁₁₂ in Formula 301 may each independently be selected from:

-   -   a phenylene group, a naphthylene group, a phenanthrenylene         group, and a pyrenylene group; and     -   a phenylene group, a naphthylene group, a phenanthrenylene         group, and a pyrenylene group, each substituted with at least         one selected from a phenyl group, a naphthyl group, and an         anthracenyl group.

Ar₁₁₃ to Ar₁₁₆ in Formula 301 may each independently be selected from:

-   -   a C₁-C₁₀ alkyl group, a phenyl group, a naphthyl group, a         phenanthrenyl group, and a pyrenyl group; and     -   a phenyl group, a naphthyl group, a phenanthrenyl group, and a         pyrenyl group, each substituted with at least one selected from         a phenyl group, a naphthyl group, and an anthracenyl group.

g, h, l, and j in Formula 301 may each independently be an integer from 0 to 4, for example, 0, 1, or 2.

Ar₁₁₃ to Ar₁₁₆ in Formula 301 may each independently be selected from:

-   -   a C₁-C₁₀ alkyl group substituted with at least one selected from         a phenyl group, a naphthyl group, and an anthracenyl group;     -   a phenyl group, a naphthyl group, an anthracenyl group, a         pyrenyl group, a phenanthrenyl group, and a fluorenyl group;     -   a phenyl group, a naphthyl group, an anthracenyl group, a         pyrenyl group, a phenanthrenyl group, and a fluorenyl group,         each substituted with at least one selected from deuterium, —F,         —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an         amino group, an amidino group, a hydrazine group, a hydrazone         group, a carboxylic acid group or a salt thereof, a sulfonic         acid group or a salt thereof, a phosphoric acid group or a salt         thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀         alkynyl group, a C₁-C₆₀ alkoxy group, a phenyl group, a naphthyl         group, an anthracenyl group, a pyrenyl group, a phenanthrenyl         group, and a fluorenyl group; and

-   -   but embodiments of the present disclosure are not limited         thereto.

In one or more embodiments, the host may include a compound represented by Formula 302 below:

Ar₁₂₂ to Ar₁₂₅ in Formula 302 are the same as described in detail in connection with Ar₁₁₃ in Formula 301.

Ar₁₂₆ and Ar₁₂₇ in Formula 302 may each independently be a C₁-C₁₀ alkyl group (for example, a methyl group, an ethyl group, or a propyl group).

k and l in Formula 302 may each independently be an integer from 0 to 4. For example, k and l may be 0, 1, or 2.

The compound represented by Formula 301 and the compound represented by Formula 302 may include Compounds H1 to H42 illustrated below, but are not limited thereto.

When the organic light-emitting device is a full-color organic light-emitting device, the emission layer may be patterned into a red emission layer, a green emission layer, and a blue emission layer. In one or more embodiments, due to a stacked structure including a red emission layer, a green emission layer, and/or a blue emission layer, the emission layer may emit white light.

When the emission layer includes a host and a dopant, an amount of the dopant may be in a range of about 0.01 parts by weight to about 15 parts by weight based on 100 parts by weight of the host, but embodiments of the present disclosure are not limited thereto.

A thickness of the emission layer may be in a range of about 100 Å to about 1,000 Å, for example, about 200 Å to about 600 Å. While not wishing to be bound by theory, it is understood that when the thickness of the emission layer is within this range, excellent light-emission characteristics may be obtained without a substantial increase in driving voltage.

Then, an electron transport region may be disposed on the emission layer.

The electron transport region may include a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.

For example, the electron transport region may have a hole blocking layer/electron transport layer/electron injection layer structure or an electron transport layer/electron injection layer structure, but the structure of the electron transport region is not limited thereto. The electron transport layer may have a single-layered structure or a multi-layered structure including two or more different materials.

Conditions for forming the hole blocking layer, the electron transport layer, and the electron injection layer which constitute the electron transport region may be understood by referring to the conditions for forming the hole injection layer.

When the electron transport region includes a hole blocking layer, the hole blocking layer may include, for example, at least one of BCP, Bphen, and BAlq but embodiments of the present disclosure are not limited thereto.

A thickness of the hole blocking layer may be in a range of about 20 Å to about 1,000 Å, for example, about 30 Å to about 300 Å. While not wishing to be bound by theory, it is understood that when the thickness of the hole blocking layer is within these ranges, the hole blocking layer may have improved hole blocking ability without a substantial increase in driving voltage.

The electron transport layer may further include at least one selected from BCP, Bphen, Alq₃, BAlq, TAZ, and NTAZ.

In one or more embodiments, the electron transport layer may include at least one of ET1 and ET25, but are not limited thereto:

A thickness of the electron transport layer may be in a range of about 100 Å to about 1,000 Å, for example, about 150 Å to about 500 Å. While not wishing to be bound by theory, it is understood that when the thickness of the electron transport layer is within the range described above, the electron transport layer may have satisfactory electron transport characteristics without a substantial increase in driving voltage.

Also, the electron transport layer may further include, in addition to the materials described above, a metal-containing material.

The metal-containing material may include a L₁ complex. The L₁ complex may include, for example, Compound ET-D1 (lithium 8-hydroxyquinolate, LiQ) or ET-D2:

The electron transport region may include an electron injection layer that promotes flow of electrons from the second electrode 19 thereinto.

The electron injection layer may include at least one selected from LiF, NaCl, CsF, Li₂O, and BaO.

A thickness of the electron injection layer may be in a range of about 1 Å to about 100 Å, for example, about 3 Å to about 90 Å. While not wishing to be bound by theory, it is understood that when the thickness of the electron injection layer is within the range described above, the electron injection layer may have satisfactory electron injection characteristics without a substantial increase in driving voltage.

The second electrode 19 is disposed on the organic layer 15. The second electrode 19 may be a cathode. A material for forming the second electrode 19 may be selected from metal, an alloy, an electrically conductive compound, and a combination thereof, which have a relatively low work function. For example, lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), or magnesium-silver (Mg—Ag) may be used as a material for forming the second electrode 19. In one or more embodiments, to manufacture a top-emission type light-emitting device, a transmissive electrode formed using ITO or IZO may be used as the second electrode 19.

Hereinbefore, the organic light-emitting device has been described with reference to the FIGURE, but embodiments of the present disclosure are not limited thereto.

Another aspect of the present disclosure provides a diagnostic composition including at least one organometallic compound represented by Formula 1.

The organometallic compound represented by Formula 1 provides high luminescent efficiency. Accordingly, a diagnostic composition including the organometallic compound may have high diagnostic efficiency.

The diagnostic composition may be used in various applications including a diagnosis kit, a diagnosis reagent, a biosensor, and a biomarker.

The term “C₁-C₆₀ alkyl group” as used herein refers to a linear or branched saturated aliphatic hydrocarbon monovalent group having 1 to 60 carbon atoms, and non-limiting examples thereof include a methyl group, an ethyl group, a propyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, an iso-amyl group, and a hexyl group. The term “C₁-C₆₀ alkylene group” as used herein refers to a divalent group having the same structure as the C₁-C₆₀ alkyl group.

The term “C₁-C₆₀ alkoxy group” as used herein refers to a monovalent group represented by —OA₁₀₁ (wherein A₁₀₁ is the C₁-C₆₀ alkyl group), and non-limiting examples thereof include a methoxy group, an ethoxy group, and an iso-propyloxy group.

The term “C₂-C₆₀ alkenyl group” as used herein refers to a hydrocarbon group formed by including at least one carbon-carbon double bond in the middle or at the terminus of the C₂-C₆₀ alkyl group, and examples thereof include an ethenyl group, a propenyl group, and a butenyl group. The term “C₂-C₆₀ alkenylene group” as used herein refers to a divalent group having the same structure as the C₂-C₆₀ alkenyl group.

The term “C₂-C₆₀ alkynyl group” as used herein refers to a hydrocarbon group formed by including at least one carbon-carbon triple bond in the middle or at the terminus of the C₂-C₆₀ alkyl group, and examples thereof include an ethynyl group, and a propynyl group. The term “C₂-C₆₀ alkynylene group” as used herein refers to a divalent group having the same structure as the C₂-C₆₀ alkynyl group.

The term “C₃-C₁₀ cycloalkyl group” as used herein refers to a monovalent saturated hydrocarbon monocyclic group having 3 to 10 carbon atoms, and non-limiting examples thereof include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. The term “C₃-C₁₀ cycloalkylene group” as used herein refers to a divalent group having the same structure as the C₃-C₁₀ cycloalkyl group.

The term “C₁-C₁₀ heterocycloalkyl group” as used herein refers to a monovalent saturated monocyclic group having at least one heteroatom selected from N, O, P, Si and S as a ring-forming atom and 1 to 10 carbon atoms, and non-limiting examples thereof include a tetrahydrofuranyl group, and a tetrahydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkylene group” as used herein refers to a divalent group having the same structure as the C₁-C₁₀ heterocycloalkyl group.

The term “C₃-C₁₀ cycloalkenyl group” as used herein refers to a monovalent monocyclic group that has 3 to 10 carbon atoms and at least one carbon-carbon double bond in the ring thereof and that has no aromaticity, and non-limiting examples thereof include a cyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group. The term “C₃-C₁₀ cycloalkenylene group” as used herein refers to a divalent group having the same structure as the C₃-C₁₀ cycloalkenyl group.

The term “C₁-C₁₀ heterocycloalkenyl group” as used herein refers to a monovalent monocyclic group that has at least one heteroatom selected from N, O, P, Si, and S as a ring-forming atom, 1 to 10 carbon atoms, and at least one carbon-carbon double bond in its ring. Examples of the C₁-C₁₀ heterocycloalkenyl group are a 2,3-dihydrofuranyl group, and a 2,3-dihydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkenylene group” as used herein refers to a divalent group having the same structure as the C₁-C₁₀ heterocycloalkenyl group.

The term “C₆-C₆₀ aryl group” as used herein refers to a monovalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms, and the term “C₆-C₆₀ arylene group” as used herein refers to a divalent group having a carbocyclic aromatic system having 6 to 60 carbon atoms. Non-limiting examples of the C₆-C₆₀ aryl group include a phenyl group, a naphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, and a chrysenyl group. When the C₆-C₆₀ aryl group and the C₆-C₆₀ arylene group each include two or more rings, the rings may be fused to each other.

The term “C₁-C₆₀ heteroaryl group” as used herein refers to a monovalent group having a carbocyclic aromatic system that has at least one heteroatom selected from N, O, P, Si, and S as a ring-forming atom, and 1 to 60 carbon atoms. The term “C₁-C₆₀ heteroarylene group” as used herein refers to a divalent group having a carbocyclic aromatic system that has at least one heteroatom selected from N, O, P, and S as a ring-forming atom, and 1 to 60 carbon atoms. Non-limiting examples of the C₁-C₆₀ heteroaryl group include a pyridinyl group, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinyl group, and an isoquinolinyl group. When the C₁-C₆₀ heteroaryl group and the C₁-C₆₀ heteroarylene group each include two or more rings, the rings may be fused to each other.

The term “C₆-C₆₀ aryloxy group” as used herein indicates —OA₁₀₂ (wherein A₁₀₂ is the C₆-C₆₀ aryl group), the term “a C₆-C₆₀ arylthio group” as used herein indicates —SA₁₀₃ (wherein A₁₀₃ is the C₆-C₆₀ aryl group), and the term “C₇-C₆₀ arylalkyl group” as used herein indicates -A₁₀₄A₁₀₅ (wherein A₁₀₄ is the C₆-C₅₉ aryl group and A₁₀₅ is the C₁-C₅₃ alkyl group).

The term “C₁-C₆₀ heteroaryloxy group” as used herein refers to —OA₁₀₆ (wherein A₁₀₆ is the C₆-C₆₀ heteroaryl group), and the term “C₁-C₆₀ heteroarylthio group” as used herein indicates —SA₁₀₇ (wherein A₁₀₇ is the C₁-C₆₀ heteroaryl group).

The term “C₂-C₆₀ heteroarylalkyl group” as used herein refers to -A₁₀₈A₁₀₉ (A₁₀₉ is a C₁-C₅₉ heteroaryl group, and A₁₀₈ is a C₁-C₅₈ alkylene group).

The term “monovalent non-aromatic condensed polycyclic group” as used herein refers to a monovalent group (for example, having 8 to 60 carbon atoms) having two or more rings condensed to each other, only carbon atoms as ring-forming atoms, and having no aromaticity in its entire molecular structure. Examples of the monovalent non-aromatic condensed polycyclic group include a fluorenyl group. The term “divalent non-aromatic condensed polycyclic group,” as used herein, refers to a divalent group having the same structure as the monovalent non-aromatic condensed polycyclic group.

The term “monovalent non-aromatic condensed heteropolycyclic group” as used herein refers to a monovalent group (for example, having 2 to 60 carbon atoms) having two or more rings condensed to each other, a heteroatom selected from N, O, P, Si, and S, other than carbon atoms, as a ring-forming atom, and having no aromaticity in its entire molecular structure. Non-limiting examples of the monovalent non-aromatic condensed heteropolycyclic group include a carbazolyl group. The term “divalent non-aromatic condensed heteropolycyclic group” as used herein refers to a divalent group having the same structure as the monovalent non-aromatic condensed heteropolycyclic group.

The term “C₅-C₃₀ carbocyclic group” as used herein refers to a saturated or unsaturated cyclic group having, as a ring-forming atom, 5 to 30 carbon atoms only. The C₅-C₃₀ carbocyclic group may be a monocyclic group or a polycyclic group.

The term “C₁-C₃₀ heterocyclic group” as used herein refers to a saturated or unsaturated cyclic group having, as a ring-forming atom, at least one heteroatom selected from N, O, Si, P, and S other than 1 to 30 carbon atoms. The C₁-C₃₀ heterocyclic group may be a monocyclic group or a polycyclic group.

At least one substituent of the substituted C₅-C₃₀ carbocyclic group, the substituted C₂-C₃₀ heterocyclic group, the substituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, the substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group, the substituted C₇-C₆₀ arylalkyl group, the substituted C₁-C₆₀ heteroaryl group, the substituted C₁-C₆₀ heteroaryloxy group, the substituted C₁-C₆₀ heteroarylthio group, the substituted C₂-C₆₀ heteroarylalkyl group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group may be selected from:

-   -   deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H,         —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino         group, an amidino group, a hydrazine group, a hydrazone group, a         carboxylic acid group or a salt thereof, a sulfonic acid group         or a salt thereof, a phosphoric acid group or a salt thereof, a         C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl         group, and a C₁-C₆₀ alkoxy group;     -   a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl         group, and a C₁-C₆₀ alkoxy group, each substituted with at least         one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H,         —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a         nitro group, an amino group, an amidino group, a hydrazine         group, a hydrazone group, a carboxylic acid group or a salt         thereof, a sulfonic acid group or a salt thereof, a phosphoric         acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a         C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a         C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀         aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl         group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group,         a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a         monovalent non-aromatic condensed polycyclic group, a monovalent         non-aromatic condensed heteropolycyclic group, —N(Q₁₁)(Q₁₂),         —Si(Q₁₃)(Q₁₄)(Q₁₅), —Ge(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇),         —P(═O)(Q₁₈)(Q₁₉), and —P(Q₁₈)(Q₁₉);     -   a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a         C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a         C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio         group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a         C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a         C₂-C₆₀ heteroarylalkyl group, a monovalent non-aromatic         condensed polycyclic group, and a monovalent non-aromatic         condensed heteropolycyclic group;     -   a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a         C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a         C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio         group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a         C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a         C₂-C₆₀ heteroarylalkyl group, a monovalent non-aromatic         condensed polycyclic group, and a monovalent non-aromatic         condensed heteropolycyclic group, each substituted with at least         one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H,         —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a         nitro group, an amino group, an amidino group, a hydrazine         group, a hydrazone group, a carboxylic acid group or a salt         thereof, a sulfonic acid group or a salt thereof, a phosphoric         acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀         alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a         C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a         C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a         C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio         group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a         C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a         C₂-C₆₀ heteroarylalkyl group, a monovalent non-aromatic         condensed polycyclic group, a monovalent non-aromatic condensed         heteropolycyclic group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅),         —Ge(Q₂₃)(Q₂₄)(Q₂₅), —B(Q₂₆)(Q₂₇), —P(═O)(Q₂₈)(Q₂₉), and         —P(Q₂₈)(Q₂₉); and     -   —N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —Ge(Q₃₃)(Q₃₄)(Q₃₅),         —B(Q₃₆)(Q₃₇), —P(═O)(Q₃₈)(Q₃₉), and —P(Q₃₈)(Q₃₉), and     -   Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ may each         independently be selected from hydrogen, deuterium, —F, —Cl,         —Br, —I, a hydroxyl group, a cyano group, a nitro group, an         amino group, an amidino group, a hydrazine group, a hydrazone         group, a carboxylic acid group or a salt thereof, a sulfonic         acid group or a salt thereof, a phosphoric acid group or a salt         thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀         alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group,         a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a         C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀         aryl group substituted with at least one selected from a C₁-C₆₀         alkyl group and a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a         C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀         heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀         heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a         monovalent non-aromatic condensed polycyclic group, and a         monovalent non-aromatic condensed heteropolycyclic group.

Hereinafter, an organometallic compound and an organic light-emitting device according to embodiments are described in detail with reference to Synthesis Examples and Examples. However, the organic light-emitting device is not limited thereto. The wording “B was used instead of A” used in describing Synthesis Examples means that an amount of A used was identical to an amount of B used, in terms of a molar equivalent.

EXAMPLES Synthesis Example 1: Synthesis of Compound 2 Synthesis of Intermediate A2

4.57 grams (g) (18.43 millimolar, mmol) of 1,3-dichlorobenzoquinoline, 5.96 g (20.27 mmol) of 2-benzofuranopinacolboronic ester, 1.19 g (1.29 mmol) of Pd(PPh₃)₄, and 2.93 g (27.64 mmol) of Na₂CO₃ were mixed with 60 milliliters (mL) of tetrahydrofuran (THF) and 30 mL of distilled water. The resultant mixture was stirred at a temperature of 75° C. for 18 hours and cooled to room temperature. The an organic layer was extracted from the resultant mixture by using ethyl acetate, and anhydrous magnesium sulfate (MgSO₄) was added to remove water from the organic layer. The dried organic layer was filtered, and a filtrate was concentrated under reduced pressure. The residue obtained from the filtrate was purified by column chromatography with dichloromethane:hexane═1:4 as an eluent to obtain 1.75 g (25%) of Intermediate A2. The obtained compound was identified by LCMS and ¹H NMR.

¹H NMR (CDCl₃) δ 9.89 (d, 1H), 8.83 (s, 1H), 8.57 (d, 1H), 8.04 (m, 5H), 7.73 (m, 3H), 7.55 (q, 2H), 7.43 (t, 1H).

MS: m/z 380.14 [(M+1)⁺].

Synthesis of Intermediate A₁

3.29 g (8.66 mmol) of Intermediate A2, 1.27 g (10.39 mmol) of phenylboronic acid, 0.56 g (0.61 mmol) of Pd(PPh₃)₄, and 1.80 g (12.99 mmol) of K₂CO₃ were mixed with 30 mL of THF and 15 mL of distilled water. The resultant mixture was stirred at a temperature of 75° C. for 18 hours and cooled to room temperature. The organic layer was extracted from the resultant mixture by using dichloromethane, and anhydrous magnesium sulfate (MgSO₄) was added to remove water from the organic layer. The dried organic layer was filtered to obtain a filtrate, and the filtrate was concentrated under reduced pressure. The residue obtained from the filtrate was recrystallized by using ethyl acetate to obtain 1.98 g (54%) of Intermediate A₁. The obtained compound was identified by LCMS and ¹H NMR.

¹H NMR (CDCl₃) δ 8.53 (d, 1H), 8.47 (s, 1H), 8.18 (d, 1H), 8.04 (m, 3H), 7.90 (d, 1H), 7.71 (d, 1H), 7.64 (d, 1H), 7.56 (m, 6H), 7.48 (m, 2H), 7.39 (t, 1H), 7.20 (m, 1H).

MS: m/z 422.15 [(M+1)⁺].

Synthesis of Intermediate M1A

1.98 g (4.70 mmol) of Intermediate A1 and 0.82 g (2.32 mmol) of iridium chloride were mixed with 30 mL of ethoxyethanol and 10 mL of distilled water. The resultant mixture was stirred under reflux for 24 hours and cooled to room temperature. Solid matter produced therefrom was filtered and separated, and then sufficiently consecutively washed with water, methanol, and hexane in that particular order. A solid obtained therefrom was dried in a vacuum oven to obtain 1.88 g (76%) of Intermediate M1A.

Synthesis of Compound 2

1.88 g (0.88 mmol) of Intermediate M1A, 0.90 g (8.80 mmol) of acetylacetone, and 0.52 g (4.40 mmol) of K₂CO₃ were mixed with 10 mL of 2-ethoxyethanol. The resultant mixture was stirred at room temperature for 15 hours to complete the reaction. A mixture obtained therefrom was filtered to obtain a solid. The solid was thoroughly washed by using ethanol and hexane, and column chromatography was performed thereon with ethylacetate:hexane═1:5 as an eluent to obtain 0.98 g (49%) of Compound 2. The obtained compound was identified by LCMS and ¹H NMR.

¹H-NMR (CDCl₃) δ 8.57 (d, 2H), 8.50 (s, 2H), 8.21 (d, 2H), 8.06 (m, 6H), 7.93 (d, 2H), 7.65 (d, 2H), 7.57 (m, 12H), 7.50 (m, 4H), 7.41 (t, 2H), 7.25 (m, 2H), 4.23 (s, 1H), 2.34 (s, 6H).

MS: m/z 1133.17 [(M+1)⁺].

Synthesis Example 2: Synthesis of Compound 5 Synthesis of Intermediate B1

2.73 g (7.18 mmol) of Intermediate A2 and 1.75 g (71.8 mmol) of magnesium turnings were mixed with 40 mL of THF and stirred under reflux for 3 hours. After the resultant mixture was cooled to a temperature of 0° C., 1.56 g (14.4 mmol) of chlorotrimethylsilane was slowly added thereto. The resultant mixture was stirred at room temperature for 2 hours. After the reaction was completed, distilled water was added thereto, and an organic layer was extracted therefrom by using ethyl acetate. Then, anhydrous magnesium sulfate (MgSO₄) was added to remove water from the organic layer. The dried organic layer was filtered to obtain a filtrate. A residue obtained from the filtrate was purified by column chromatography with ethylacetate:hexane═1:8 as an eluent to obtain 1.22 g (41%) of Intermediate B1. The obtained compound was identified by LCMS and ¹H NMR.

¹H NMR (CDCl₃) δ 8.55 (d, 1H), 8.23 (s, 1H), 8.17 (d, 1H), 7.94 (m, 5H), 7.63 (m, 3H), 7.50 (q, 2H), 7.33 (t, 1H), 0.09 (s, 9H).

MS: m/z 418.15 [(M+1)⁺].

Synthesis of Compound M1B

1.22 g (2.92 mmol) of Intermediate B1 and 0.51 g (1.44 mmol) of iridium chloride were mixed with 30 mL of ethoxyethanol and 10 mL of distilled water. The resultant mixture was stirred under reflux for 24 hours to complete the reaction, and then cooled to room temperature. Solid matter produced therefrom was filtered and separated, and then thoroughly washed with water, methanol, and hexane in that particular order. A solid obtained therefrom was dried in a vacuum oven to obtain 1.20 g (78%) of Intermediate M1B.

Synthesis of Compound 5

1.20 g (0.57 mmol) of Intermediate M1B, 0.58 mL (5.66 mmol) of acetylacetone, and 0.39 g (2.83 mmol) of K₂CO₃ were mixed with 10 mL of 2-ethoxyethanol. The resultant mixture was stirred at room temperature for 15 hours to complete the reaction. A mixture obtained therefrom was filtered to obtain a solid. The solid was thoroughly washed by using ethanol and hexane and purified by column chromatography with ethylacetate:hexane═1:7 to obtain 0.48 g (38%) of Compound 5. The obtained compound was identified by LCMS and ¹H NMR.

¹H-NMR (CDCl₃) δ 8.65 (d, 2H), 8.33 (s, 2H), 8.20 (d, 2H), 7.98 (m, 8H), 7.63 (m, 6H), 7.55 (q, 4H), 7.31 (t, 2H), 4.23 (s, 1H), 2.34 (s, 6H), (s, 18H).

MS: m/z 1125.30 [(M+1)⁺].

Synthesis Example 3: Synthesis of Compound 8

0.50 g (50%) of Compound 8 was synthesized in the same manner as Compound 2 in Synthesis Example 1, except that 0.86 g (0.40 mmol) of Intermediate M1A was used and 0.85 g (4.02 mmol) of 3,7-diethylnonein-4,6-dione was used instead of acetylacetone. The obtained compound was identified by LCMS and 1H NMR.

¹H-NMR (CDCl₃) δ 8.57 (d, 2H), 8.50 (s, 2H), 8.21 (d, 2H), 8.06 (m, 6H), 7.93 (d, 2H), 7.65 (d, 2H), 7.57 (m, 12H), 7.50 (m, 4H), 7.41 (t, 2H), 7.25 (m, 2H), 4.24 (s, 1H), 2.28 (m, 2H), 1.31 (m, 8H), 0.98 (t, 12H).

MS: m/z 1245.41 [(M+1)⁺].

Example 1

An ITO glass substrate was cut to a size of 50 mm×50 mm×0.5 mm (mm=millimeter), sonicated with acetone, iso-propyl alcohol, and pure water, each for 15 minutes, and then cleaned by exposure to ultraviolet (UV) rays and ozone for 30 minutes.

Then, m-MTDATA was deposited on an ITO electrode (anode) on the ITO glass substrate at a deposition rate of 1 Angstroms per second (Å/sec) to form a hole injection layer having a thickness of 600 Angstroms (Å), and α-NPD was deposited on the hole injection layer at a deposition rate of 1 Å/sec to form a hole transport layer having a thickness of 250 Å.

Compound 2 (dopant) and CBP (host) were respectively co-deposited on the hole transport layer at deposition rates of 0.1 Å/sec and 1 Å/sec to form an emission layer having a thickness of 400 Å.

BAlq was deposited on the emission layer at a deposition rate of 1 Å/sec to form a hole blocking layer having a thickness of 50 Å, Alq₃ was deposited on the hole blocking layer to form an electron transport layer having a thickness of 300 Å, LiF was deposited on the electron transport layer to form an electron injection layer having a thickness of 10 Å, and Al was vacuum-deposited on the electron injection layer to form a second electrode (cathode) having a thickness of 1,200 Å, thereby completing the manufacture of an organic light-emitting device having a structure of ITO/m-MTDATA (600 Å)/α-NPD (250 Å)/CBP+Compound 2 (10%) (400 Å)/BAlq (50 Å)/Alq₃ (300 Å)/LiF (10 Å)/Al (1,200 Å).

Examples 2 and 3 and Comparative Examples a to C

Organic light-emitting devices were manufactured in the same manner as in Example 1, except that Compounds shown in Table 2 were each used instead of Compound 1 as a dopant in forming an emission layer.

Evaluation Example 1: Evaluation of Characteristics of Organic Light-Emitting Devices

The driving voltage, luminescent efficiency, color purity, quantum emission efficiency, and lifespan (T₉₅) of the organic light-emitting devices manufactured according to Examples 1 to 3 and Comparative Examples A to C. Evaluation results thereof are shown in Table 2. A current-voltage meter (Keithley 2400) and a luminance meter (Minolta Cs-1000A) were used as evaluation apparatuses, and the lifespan (T₉₅) (at 6000 nit) indicates an amount of time that had elapsed when luminance was 95% of initial luminance (100%).

TABLE 2 Quantum Driving Luminescent emission Lifespan voltage efficiency efficiency (hr) Dopant (V) (cd/A) CIEx CIEy (%) (T₉₅) Example 1 Compound 2 3.73 32.5 0.62 0.36 23.9 1750 Example 2 Compound 5 3.80 26.7 0.63 0.35 23.2 1470 Example 3 Compound 8 3.81 30.3 0.64 0.36 24.1 1350 Comparative Compound A 4.35 25.5 0.65 0.34 24.1 1000 Example A Comparative Compound B 4.54 14.0 0.62 0.35 10.3 330 Example B Comparative Compound C 4.41 17.8 0.62 0.37 13.1 300 Example C

Referring to Table 2, it has been determined that the organic light-emitting devices of Examples 1 to 3 have improved driving voltage, luminescent efficiency, quantum emission efficiency, and lifespan characteristics, as compared with those of the organic light-emitting devices of Comparative Examples A to C.

Since the organometallic compounds have excellent electrical characteristics and thermal stability, organic light-emitting devices including such organometallic compounds may have excellent driving voltage, luminescent efficiency, quantum emission efficiency, roll-off ratio, and lifespan characteristics.

It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments.

While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the following claims. 

What is claimed is:
 1. An organometallic compound represented by Formula 1: M(L₁)_(n1)(L₂)_(n2)  Formula 1

wherein M in Formula 1 is selected from iridium (Ir), platinum (Pt), osmium (Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), thulium (Tm), rhodium (Rh), ruthenium (Ru), and rhenium (Re), in Formula 1, L₁ is a ligand represented by Formula 2, and n1 is 1 or 2, wherein, when n1 is two, two groups L₁ are identical to each other, in Formula 1, L₂ is selected from a monovalent organic ligand, a divalent organic ligand, a trivalent organic ligand, and a tetravalent organic ligand, and n2 is 1, or 2, wherein, when n2 is two, two groups L₂ are identical to each other, Li and L₂ in Formula 1 are different from each other, * and *′ in Formula 2 each indicate a binding site to M in Formula 1, in Formula 2, Y₉ is carbon, and a bond between N and Y₉ in CY₁ is a single bond or a double bond, a moiety represented by

in Formula 2 is selected from a group represented by Formulae CY1-1, CY1-2, CY1-5, CY1-6, CY1-7, and CY1-8:

X₁ in Formula 2 is O, S, S(═O)₂, Se, or N(R₂₁), in Formula 2, Y₁ is N, C(R₁), carbon bonded to Y₉, or carbon bonded to M, Y₂ is N, C(R₂), carbon bonded to Y₉, or carbon bonded to M, Y₃ is N, C(R₃), carbon bonded to Y₉, or carbon bonded to M, Y₄ is N, C(R₄), carbon bonded to Y₉, or carbon bonded to M, Y₅ is N or C(R₅), Y₆ is N or C(R₆), Y₇ is N or C(R₇), Y₈ is N or C(R₈), and one of Y₁ to Y₄ is carbon bonded to Y₉ while another of Y₁ to Y₄ is carbon bonded to M, R₁ to R₈, R₁₁ to R₁₈, and R₂₁ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, —SF₅, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₇-C₆₀ arylalkyl group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted C₁-C₆₀ heteroaryloxy group, a substituted or unsubstituted C₁-C₆₀ heteroarylthio group, a substituted or unsubstituted C₂-C₆₀ heteroarylalkyl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —Ge(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), —P(═O)(Q₈)(Q₉), and —P(Q₈)(Q₉), provided that at least one of i) and ii) is true i) at least one of Y1 to Y8 is N, or ii) a moiety represented by

in Formula 2 is selected from a group represented by Formulae CY1-2, CY1-5, and CY1-8; a10 is an integer from 0 to 8, two or more groups selected from R₁ to R₄ in Formula 2 are optionally linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₂-C₃₀ heterocyclic group, two or more groups selected from R₅ to R₈ in Formula 2 are optionally linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₂-C₃₀ heterocyclic group, two or more groups selected from a plurality of groups Ru to Rib, in Formulae CY1-1, CY1-2, CY1-5, CY1-6, CY1-7, and CY1-8 are optionally linked to form a substituted or unsubstituted C₅-C₃₀ carbocyclic group or a substituted or unsubstituted C₂-C₃₀ heterocyclic group, at least one substituent of the substituted C₅-C₃₀ carbocyclic group, the substituted C₂-C₃₀ heterocyclic group, the substituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, the substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group, the substituted C₇-C₆₀ arylalkyl group, the substituted C₁-C₆₀ heteroaryl group, the substituted C₁-C₆₀ heteroaryloxy group, the substituted C₁-C₆₀ heteroarylthio group, the substituted C₂-C₆₀ heteroarylalkyl group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group is selected from: deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), —Ge(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇), —P(═O)(Q₁₈)(Q₁₉), and —P(Q₁₈)(Q₁₉); a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅), —Ge(Q₂₃)(Q₂₄)(Q₂₅), —B(Q₂₆)(Q₂₇), —P(═O)(Q₂₈)(Q₂₉), and —P(Q₂₈)(Q₂₉); and —N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —Ge(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), —P(═O)(Q₃₈)(Q₃₉), and —P(Q₃₈)(Q₃₉), and Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryl group substituted with at least one selected from a C₁-C₆₀ alkyl group and a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group.
 2. The organometallic compound of claim 1, wherein, in Formula 1, M is Ir or Os, and the sum of n1 and n2 is 3; or M is Pt, and the sum of n1 and n2 is
 2. 3. The organometallic compound of claim 1, wherein a moiety represented by

in Formula 2 is selected from a group represented by Formulae CY1-2, CY1-5, CY1-7, and CY1-8, and X₁ is O or S.
 4. The organometallic compound of claim 1, wherein R₁ to R₈, and R₂₁ are each independently selected from: hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, —SF₅, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group; a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₁₀ alkyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[2.2.2]octyl group, a phenyl group, a naphthyl group, a pyridinyl group, and a pyrimidinyl group; a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[2.2.2]octyl group, a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group; a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[2.2.2]octyl group, a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[2.2.2]octyl group, a phenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and —Si(Q₃₃)(Q₃₄)(Q₃₅); and —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —Ge(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), —P(═O)(Q₈)(Q₉), and —P(Q₈)(Q₉), and Q₁ to Q₉ and Q₃₃ to Q₃₅ are each independently selected from: —CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CD_(H)2, —CHDCH₃, —CHDCD₂H, —CHDCD_(H)2, —CHDCD₃, —CD₂CD₃, —CD₂CD₂H, and —CD₂CDH₂; an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group; and an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group, each substituted with at least one selected from deuterium, a C₁-C₁₀ alkyl group, and a phenyl group.
 5. The organometallic compound of claim 1, wherein R₁ to R₈, R₁₁ to R₁₈, and R₂₁ are each independently selected from hydrogen, deuterium, —F, a cyano group, a nitro group, —SF₅, —CH₃, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, groups represented by Formulae 9-1 to 9-20, groups represented by Formulae 10-1 to 10-142, —Si(Q₃)(Q₄)(Q₅), and —Ge(Q₃)(Q₄)(Q₅), and Q₃ to Q₅ are each independently selected from: —CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂, —CHDCH₃, —CHDCD₂H, —CHDCDH₂, —CHDCD₃, —CD₂CD₃, —CD₂CD₂H, and —CD₂CDH₂; an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group; and an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group, each substituted with at least one selected from deuterium, a C₁-C₁₀ alkyl group, and a phenyl group,

wherein, in Formulae 9-1 to 9-20 and 10-1 to 10-142, “Ph” indicates a phenyl group, “TMS” indicates a trimethylsilyl group, and * indicates a binding site to a neighboring atom.
 6. The organometallic compound of claim 1, wherein a moiety represented by

in Formula 2 is a group represented by Formula CY1-1 and at least one of Y₁ to Y₈ is N.
 7. The organometallic compound of claim 1, wherein a moiety represented by

in Formula 2 is a group represented by Formula CY1-1, R₁₁ in Formula CY1-1 is not hydrogen and at least one of Y₁ to Y₈ is N.
 8. The organometallic compound of claim 1, wherein L₁ in Formula 1 is selected from ligands represented by Formulae 2-1 to 2-6:


9. The organometallic compound of claim 1, wherein Li in Formula 1 is a ligand represented by Formula 2A:

wherein, in Formula 2A, Y₈ is N, X₁, R₃ to R₆R₇, *′ are each independently the same as described in claim 1, and R₁₁ to R₁₈ are each independently the same as described in connection with R₁₀ in claim
 1. 10. The organometallic compound of claim 9, wherein at least one of R₃ and R₁₁ is not hydrogen.
 11. The organometallic compound of claim 1, wherein L₂ in Formula 1 is selected from ligands represented by Formulae 3A to 3F:

wherein, in Formulae 3A to 3F, Y₁₁ is selected from O, N, N(Z₁), P(Z₁)(Z₂), and As(Z₁)(Z₂), Y₁₂ is O, N, N(Z₃), P(Z₃)(Z₄), and As(Z₃)(Z₄), T₁₁ is selected from a single bond, a double bond, *—C(Z₁₁)(Z₁₂)—*′, *—C(Z₁₁)═C(Z₁₂)—*′, *═C(Z₁₁)—*′, *—C(Z₁₁)=*′, *═C(Z₁₁)—C(Z₁₂)═C(Z₁₃)—*′, *—C(Z₁₁)═C(Z₁₂)—C(Z₁₃)=*′, *—N(Z₁₁)—*′, and a substituted or unsubstituted C₆-C₃₀ arylene group, a11 is an integer from 1 to 5, Y₁₃ to Y₁₆ are each independently carbon (C) or nitrogen (N), a bond between Y₁₃ and Y₁₄ is a single bond or a double bond, and a bond between Y₁₅ and Y₁₆ is a single bond or a double bond, CY₁₁ to CY₁₃ are each independently a C₅-C₃₀ carbocyclic group or a C₂-C₃₀ heterocyclic group, A₁ is P or As, Z₁ to Z₄ and Z₁₁ to Z₁₃ are each independently the same as described in connection with R₁₀ in claim 1, d1 and d2 are each independently an integer from 0 to 10, and * and *′ each indicate a binding site to M in Formula
 1. 12. The organometallic compound of claim 11, wherein CY₁₁ to CY₁₃ are each independently selected from a benzene group, a naphthalene group, a pyridine group, a pyrimidine group, a triazine group, a pyrrole group, a pyrazole group, an imidazole group, and a triazole group.
 13. The organometallic compound of claim 1, wherein L₂ in Formula 1 is selected from ligands represented by Formulae 3-1 to 3-15:

wherein, in Formulae 3-1 to 3-15, X₃₁ is N or C(Z_(1a)), X₃₂ is N or C(Z_(1b)), X₄₁ is O, S, N(Z_(1c)), or C(Z_(1d))(Z_(1e)), Z₁ to Z₄, Z_(1a) to Z_(1e), and Z₁₁ to Z₁₄ are each independently the same as described in connection with R₁₀ in claim 1, e2 is an integer from 0 to 2, e3 is an integer from 0 to 3, e4 is an integer from 0 to 4, and * and *′ each indicate a binding site to M in Formula
 1. 14. An organic light-emitting device comprising: a first electrode; a second electrode; and an organic layer disposed between the first electrode and the second electrode, wherein the organic layer comprises an emission layer and at least one organometallic compound of claim
 1. 15. The organic light-emitting device of claim 14, wherein the first electrode is an anode, the second electrode is a cathode, and the organic layer further comprises a hole transport region disposed between the first electrode and the emission layer and an electron transport region disposed between the emission layer and the second electrode, wherein the hole transport region comprises a hole injection layer, a hole transport layer, an electron blocking layer, or any combination thereof, and wherein the electron transport region comprises a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.
 16. The organic light-emitting device of claim 14, wherein the emission layer comprises the organometallic compound.
 17. The organic light-emitting device of claim 16, wherein the emission layer further comprises a host, and an amount of the host in the emission layer is larger than an amount of the organometallic compound in the emission layer.
 18. An organometallic compound represented by Formula 1: M(L₁)_(n1)(L₂)_(n2)  Formula 1

wherein M in Formula 1 is iridium (Ir), in Formula 1, L₁ is a ligand represented by Formula 2-1, and n1 is 1 or 2, wherein, when n1 is two, two groups L₁ are identical to each other, in Formula 1, L₂ is selected from a monovalent organic ligand, a divalent organic ligand, a trivalent organic ligand, and a tetravalent organic ligand, and n2 is 1, the sum of n1 and n2 is 3, L₁ and L₂ in Formula 1 are different from each other, * and *′ in Formula 2-1 each indicate a binding site to M in Formula 1, in Formula 2-1, Y₉ is carbon, a moiety represented by

Formulae CY1-1, CY1-6, and CY1-7:

X₁ in Formula 2-1 is O, S, S(═O)₂, or Se, in Formula 2-1, Y₃ is C(R₃), Y₄ is C(R₄), Y₅ is C(R₅), Y₆ is C(R₆), Y₇ is C(R₇), and Y₈ is C(R₈), R₃ to R₈ and R₁₁ to R₁₈ are each independently selected from hydrogen, deuterium, —F, a cyano group, and a C₁-C₂₀ alkyl group; a C₁-C₂₀ alkyl group substituted with at least one selected from deuterium, —F, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a cyano group, a C₁-C₁₀ alkyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, and a bicyclo[2.2.2]octyl group; a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[2.2.2]octyl group, a phenyl group, and a naphthyl group; a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[2.2.2]octyl group, a phenyl group, and a naphthyl group, each substituted with at least one selected from deuterium, —F, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a cyano group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[2.2.2]octyl group, a phenyl group, a naphthyl group, and —Si(Q₃₃)(Q₃₄)(Q₃₅); and —Si(Q₃)(Q₄)(Q₅) and —Ge(Q₃)(Q₄)(Q₅), and provided that at least one of R₁₁ to R₁₈ is not hydrogen, Q₃ to Q₅ and Q₃₃ to Q₃₅ are each independently selected from: —CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂, —CHDCH₃, —CHDCD₂H, —CHDCDH₂, —CHDCD₃, —CD₂CD₃, —CD₂CD₂H, and —CD₂CDH₂; an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group; and an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an iso-pentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group, each substituted with at least one selected from deuterium, a C₁-C₁₀ alkyl group, and a phenyl group. 